This invention relates to clamps and the like for holding an ice skate while grinding the edge of the ice skate blade and, particularly where the clamp is manually manipulated by an operator to bring the held skate blade evenly against the edge of a stationary grinding wheel.
Heretofore, machines and apparatus have been proposed for holding an ice skate blade against a grinding wheel to grind the edge of the blade. The usual arrangement is to provide a clamp or the like rigidly holding the ice skate and a grinding wheel, all mounted to a common platform. Usually, the grinding wheel is fixed on the platform and the clamp holding the ice skate is moveable along a track on the platform so that the blade of the skate can be brought against the grinding wheel by moving the clamp along the track.
In some apparatus, the clamp is attached to the platform by a combination of hinges or pivots rather than a track, however, whether a track is used or hinges are used, movement of the clamp with respect to the grinding wheel is very limited. Furthermore, in all such prior apparatus, one jaw of the clamp is at fixed level above the base and so, it is at a fixed level with respect to the stationary grinding wheel, and the other jaw of the clamp is adjustable so that skate blades of different thicknesses can be gripped by the clamp. Thus, when the skate blade is relatively thin, the center of the blade between the two edges of the blade will be positioned slightly closer to the base than when the blade is relatively thick.
This situation is not particularly troublesome in such apparatus where the direction of grinding is perpendicular to the blade or, in other words, where the rotation axis of the grinding wheel disc lies in the plane of the blade, because the grinding wheel is usually six inches or more in diameter and the plane of the blade passing through the center of the blade shifts only a very small fraction of an inch relative to the grinding wheel axis when skate blades of different thicknesses are mounted in the apparatus for grinding. However, this small shift in the plane of the blade relative to the grinding wheel which occurs when thin or thick blades are mounted in the clamp becomes more significant in apparatus where the direction of grinding is parallel to the blade. In that case, the central plane of the blade is supposed to be aligned with the central plane of the grinding wheel disc so that they are co-planar. If it is not aligned, then the two edges of the skate blade will not be ground evenly.
The finishing grind of an ice skate blade is preferably parallel to the blade, because grinding then is in the direction of the blade rather than across it and the edges of the blade are ground smoother, sharper and without burs from end to end. However, even a slight misalignment of the central plane of the blade (through the center of the blade) with the central plane of the grinding disc (through the center of the wheel disc) could make the edges of the blade uneven.